Piston cooling means



July 11, 1961 Filed July 15, 1959 J. T. RAUSCH PISTON COOLING MEANS 2Sheets-Sheet 1 26 f I, 51 29 zv INVENTOR. $622 f/Qazzscfi ATTORNEY July11, 196"] J. T. RAUSCH PISTON COOLING MEANS 2 Sheets-Sheet 2 Filed July15, 1959 4 WW @fi/fiii i A i iiii ATTQBNEY United States Patent2,991,770 PISTON COOLING MEANS John T. Rausch, Berkley, Mich, assignorto General Motors Corporation, Detroit, Mich., a corporation of DelawareFiled July 15, 1959, Ser. No. 827,400 2 Claims. (Cl. 123-4135) Thisinvention relates to internal combustion engines, particularly tocooling the pistons of internal combustion engines and the like.

It is proposed to cool the pistons of internal combustion engines withjets of oil intermittently directed toward the head ends of the pistons.The jets of oil are metered quantities of oil supplied by the oil supplysystem for the engine and timed by the operation of the pistons of theengine. The jets are projected from ports uncovered by the pistons asthe pistons approach outer dead center positions in the cylinders. Thejets expand the oil under pressure in the lubrication system throughmetering devices which direct the jets through the inner open ends ofthe pistons and upon the head ends or other walls of the pistons.

In the drawing:

FIGURE 1 is a fragmentary cross sectional view of a V-type multicylinderinternal combustion engine that may be employed for automotive or otherpurposes.

FIGURE 2 is an enlarged fragmentary view of one of the cylinders of theengine disclosed by FIGURE 1, and with the piston of the cylinderpositioned beyond a port in the cylinder where a jet of oil from thelubricating system of the engine is being discharged upon the piston.

FIGURE 3 is a similar enlarged fragmentary view of the cylinder but withthe piston thereof closing the cooling oil supplying port.

FIGURE 4 is a fragmentary longitudinal view through one of the main oilgalleries of the engine, and disclosing a pair of valve lifters and acooling oil supply passage, all communicating with the gallery.

The engine embodying the invention has cylinders 11 in which pistons 12are reciprocated by connecting rods 13 connecting the pistons 12 withthe crankshaft 14 of the engine. The pistons are adapted to compressexplosive charges into combustion chambers 16 formed between thecylinders 11, the pistons 12 and heads 17 for the cylinders of theengine. The charges are adapted to be ignited in the combustion chambers16 at the end of the compression stroke of the pistons, and after whichthe pistons are moved away from the heads of the engine and toward theinner dead center position of the piston by expansion of the charges onthe exhaust stroke. The outward movement of the pistons will dischargethe products of combustion from the engine through exhaust valves 18,exhaust passages 19, and exhaust manifolds 21.

When the engine is operating under full power conditions the walls ofthe pistons tend to become excessively heated, this being particularlytrue of the head end walls of the pistons indicated at 22. Thisexcessive heating often causes the walls of the pistons to crack andperhaps even to break, thus rendering the engine inoperative. In orderto prevent excessive heating of the piston walls it is proposed tosupply oil to the interior surfaces of the pistons, particularly to theinside surfaces of the end walls 22. To accomplish this it is proposedto provide ports through which the oil may be discharged upon the innersurfaces of the pistons, there being one of the ports 23 for eachcylinder of the engine. It is considered preferable to locate the ports23 so that they will be uncovered by the piston somewhere between theinner and outer 2,991,770 Patented July 11, 1961 dead center positionsof the pistons, perhaps in the vicinity of 90 before the outer deadcenter position of the pistons. The ports 23 are adapted to be suppliedwith oil by metering passages 24 which communicate through supplypassages 26 with one of the main oil galleries 27 employed in supplyingoil to the valve actuating mechanism of the engine. Such actuatingmechanism may include valve lifters 28 which are operated by the earns29 of the camshaft 31 of the engine, the camshaft being driven in timedrelation by the crankshaft 14 of the engine. The valve lifters 23 may besupplied with oil by the galleries 27, in the present instance thelifters being located along the length of the galleries and in such away as to intersect the galleries. Grooves 32 are formed in the valvelifters in such a way as to at all times communicate with the galleries27, thereby to provide a continuous flow of oil in the galleria from oneend thereof to the other. It is proposed to locate the oil supplypassages 26 in such a manner as to communicate with the galleries 27between the pairs of valve lifters 28 for each cylinder 11 of theengine. The passages 26 therefore will be supplied at all times with oilunder the fulllubricating oil pressure of the engine, as this pressureis employed in lubricating the valve lifters 28 and other associatedparts of the valve actuating mechanism of the engine. The meteringorifices 24 terminating in the ports 23 meter the oil to such an extentas to maintain the desired pressure in the galleries 27 and increase thevelocity of the oil to provide the jets of oil discharged by the ports23. The position of the orifices 24 and the ports 23 is such that whenthe ports are uncovered by movement of the pistons of the engine, thejets of oil will be discharged on the inner walls of the pistons,preferably although not necessarily on the end walls 22 of the pistons.Such jets of oil when discharged on the walls of the pistons will coolthe walls, thereby preventing overheating of the pistons under full orexcessive loads on the on gine 10. t l

The claims:

1. An internal combustion engine having a reciprocating piston in acylinder and an oil passage adjacent said cylinder, said oil passagebeing supplied with lubricating oil under pressure employed inlubricating the moving parts of said engine, and piston cooling meansfor said engine, said piston cooling means comprising a port in the wallof said cylinder, said port being connected to said passage and beinguncovered by said piston during the reciprocating movement of saidpiston, said port when uncovered by said piston being positioned todischarge a jet of oil inside said piston and against the inner surfaceof the walls of said piston employed in supporting said piston in thecylinder and in expanding and exhausting the products of combustionburned in and exhausted from said cylinder, said oil being employed incooling the walls of said piston during the operation of said engine.

2. An internal combustion engine as defined by claim 1 and in which saidport embraces jet means directed toward the outer end of said cylinderand metering the oil supplied by said passage and projecting said oilfrom said port at a velocity sufficient for said oil to reach the outerend of said piston when said piston is in outer dead center position insaid cylinder.

References Cited in the file of this patent UNITED STATES PATENTS

